Just in - brand new 61-page free PST catalog

I just went to the PST site and they want $575.00 for a set of leaf springs for my 66 Valiant. My local spring guy want to charge me $600.00 dollars to install new spring with new shackles and bushings. , JC Whitney has them for $65.00 a piece. Shackles for $38.00 a peice and bushings for $13.00 a side.
Whats with the price difference. Of coarse I am leaning to JC Whitney and doing it myself. But the PST price is bit high. Am I wrong?